Method of and apparatus for processing metal strip



M. D. STONE May 10, 1966 METHOD OF AND APPARATUS FOR PROCESSING METAL STRIP Filed Aug. 25, 1958 4 Sheets-Sheet 1 INVENTOR. MORRIS D. ,5 TONE HIS ATTORNEY METHOD OF AND APPARATUS FOR PROCESSING METAL STRIP Filed Aug. 25, 1958 May 10, 1966 7 M. D. STONE 4 Sheets-Sheet 2 INVEN TOR. M ORRIS D.STONE BY HIS ATTORNEY FIG-.6

y' 1966 M. D. STONE 3,250,105

METHOD OF AND APPARATUS FOR PROCESSING METAL STRIP Filed Aug. 25, 1958 4 Sheets-Sheet 3 FIG.5

IN V EN TOR.

HIS ATTORNEY May 10, 1966 I M. D. STONE 3,250,105

METHOD OF AND APPARATUS FOR PROCESSING METAL STRIP Filed Aug. 25, 1958 4 Sheets-Sheet 4 INVEN TOR.

MORRIS D. STONE H15 ATTORNEY United States Patent gineering'and Foundry Company, Pittsburgh, Pa., a

corporation of Pennsylvania Filed Aug. 25, 1958, Ser. No. 757,057 16 Claims. (Cl. 72240) This invention relates to an improved method of and apparatus for processing metal strip and, in particular, to a method and apparatus for rolling strip to produce a final product having a uniform cross-section across its width.

Heretofore, in the rolling of metal strip, one of the most frequently encountered difficulties is that of so controlling the contour of the processing or work rolls of the mill defining the pass to produce a strip which is uniform across its width. It has been proposed to provide a rolling mill having crowned rolls, i.e., either one or both of the working or processing rolls so ground as to increase in diameter from the ends of the roll body to the center, the magnitude of the crown being so determined that for rolling strip of a certain width and metallurgical analysis,

the theory is that when the roll deflects during a rolling operation, the crown will be sufiicient to offset the displacement and thus produce a strip of essentially constant thickness. Though this may be determined for a given set of conditions, i.e., for a particular width of strip, reduction to be taken and/ or metallurgical analysis, as soon as strip of difierent characteristics is to be rolled, then, of course, there will be a change in pressure on the rolls and hence there will be a departure from the desirable constant thickness conditions.

Another solution which has been proposed in an effort to obtain constant thickness of strip in such a mill involves the use of means for applying a bending force to the necks of at least one of the unsupported mill working or processing rolls in a direction either to enhance or to reduce the machined crown of the roll as may be required. This solution has many limitations by reason of the fact that the rolls either must be subject to relatively low pressures during a processing operation or the processing rolls must of necessity be of large diameter to withstand rolling forces of any appreciable magnitude which may be imposed thereon.

It has been found, however, that for best conditions for carrying out a rolling operation, that is the ability to take rather large reductions on metal strip for each pass through the mill, relatively small diameter working or processing rolls-should be employed which, obviously,

must be supported by ultimate load carrying backing .up rolls. Here again, however, difficulties are encountered inasmuch as pressure during rolling is applied to the mill through the necks of the backing up or supporting rolls so that those rolls are caused to bow outward with respect to the rolls they support and hence the supported rolls will also be permitted to bow outward at their centers. Hence, except for the critical load which will just absorb the crown of the rolls and possibly produce a strip of uniform thickness, for all other loads imposed upon the mill strip of non-uniform thickness will be the result. If, in such mills, the solution proposed with respect to the processing rolls as discussed above should be applied to a mill of this type, it will be readily recognized that the attempt to control the contour of the processing rolls will have little or no effect, principally by reason of the fact that if the backing up or supporting rolls are crowned, the load upon the mill will normally be sufficient to cause the processing rolls to be pressed against the crowned surfaces of the backing rolls at least to the extent equal to the width of the material being rolled. In this case, also,

' the crown on the backing rolls is the controlling factor.

3,250,105 Patented May 10, 1966 ice In connection with mills having small working or processing rolls and relatively large ultimate load supporting backing up rolls, it has been proposed to provide both crowned working or processing and supporting rolls and to apply forces to the necks of the processing rolls to bend those rolls about the centers of the supporting rolls.

.Here, again, the crown of the backing up or supporting rolls will control and the forces applied to the necks of the processing rolls will have little or no eifect princlpally by reason of the fact that the load to which the mill is subjected during a rolling operation .will be sufficient to cause the processing rolls to be deflected and hug the crowned surfaces of the rolls which support them.

For overcoming the difficulties inherent in the operation of multi-high rolling mills, particularly of the nature of those expressed heretofore, the applicant has provided an arrangement whereby a bending force is imposed not upon the necks of the working or processing rolls of a mill, but rather upon the necks of the backing up or ultimate load carrying supporting rolls thereof thereby to induce a contour controlling bending moment upon such supporting or backing rolls which will assure the operator 'that a strip of uniform thickness across its width will be produced. Whether the rolls are actually crowned or not, it is seen that by embodying the features of the invention herein disclosed in a multi-high mill which includes but is not limited to four high mills as well as cluster mills, it is possible by imposing a contour controll-' ing bending moment upon the supporting rolls of such mills, production of a strip of uniform thickness will be assured.

. It is one of the objects of this invention to provide a mil-l for rolling metal strip adapted to produce a rolled product of uniform gage across its width irrespective of the width, reduction, or the metallurgical characteristics thereof.

Another object of this invention is to provide in a backed-up mill having uncrowned rolls an arrangement for imposing a contour controlling bending moment on the rolls in such a fashion as to effect a crown in the bite of varying magnitude depending upon the conditions of operation.

Still another object of this invention is to provide a method by which a crown due to bending as opposed to a machined crown may be imposed upon the rolls of a mill defining a roll pass the purpose of which will be to provide a uniform fiat pass for the strip being processed irrespective of such variables as the width or thickness of strip, the reduction being taken or the metallurgical characteristics of the metal.

The foregoing objects as well as the various other beneficial results and advantages of the invention will be apparent by referring to the specification and the accompanying drawings of which:

FIG. 1 is an end view of a mill embodying the features of the invention herein disclosed;

FIG. 2 is a side elevation of the mill shown in FIG. 1;

FIG. 3 is a schematic diagram of the hydraulic system employed with the mill shown in FIG. 1;

FIG. 4 is a schematic electrical diagram showing the electrical arrangement;

FIG. 5 is .an end elevation view of a portion of a fourhigh mill, in modified form, embodying the features of the invention herein disclosed;

FIG. 6 is a front elevation view, partly in section, of the mill shown in FIG. 5;

FIG. 7 is a front elevation view, partly in section, of another modification of the invention as applied to a particular type of cluster mill generally referred to as an X- mill, and

FIG. 8 is a side elevation view of the mill shown in FIG. 7.

With reference to FIGS. 1 and 2, the mill embodying the features of the invention disclosed herein include a base 11, a pair of housings 12 and 13, a pair of work rolls 14 mounted at their ends in suitable chocks 15 slidable within windows in the housings and a pair of relatively large diameter backing-up rolls 16 mounted at their ends in suitable chocks 17 also slidable in the windows of the housings. A screwdown mechanism 18, having vertically adjustable screws 19 connected thereto and to the chocks 17 of the backing-up rolls 16, is provided for applying variable rolling pressure to the rolls. Outward of the chocks 17 and mounted on each of the necks of the upper backing-up rolls 16 there are additional bearing housings 26 having a T shaped slot 21 at the upper portion thereof with which a T shaped member 22 is engaged. By pins 23 inserted in suitable openings at the upper end thereof, which pins 23 may be quickly withdrawn for disassembly and roll changing, members 22 are pivotally connected to the lower ends of piston rods 24 extending downward from double acting cylinders 25 secured to the upper portion of the mill adjacent to the screws 19.

To each of the necks of the lower backing-up rolls 16, there are also secured additional bearing housings 26 having T slots 27 therein within which there are re ceived T shaped members 28. By pins 29, which are also quickly detachable for purposes of disassembly and roll changing, the members 28 are pivotally secured to the ends of piston rods 31 extending upward from double acting cylinders 32 secured to the lower portion of the housings 12 and 13. The fluid pressure within the cylin- -ders 25 and 32 may be varied over a wide range and the direction of fluid flow controlled by an hydraulic and electrical system associated therewith to be presently described.

As shown in theschematic diagram FIG. 3, the hydraulic system includes a storage sump 33 for the fluid employed in the system to which there is connected by a conductor 34, having a shut-off valve 35 interposed therein, a variable constant volume pump 36 driven by a motor 37. From the pump 36 the fluid under pressure is passed through a conduit 38 having a filter 39 therein and to a relief valve 41 which is set to permit fluid to pass upward tem. Adjacent to and connected to the valve 42 there is a four-way single solenoid spring offset valve 46 from which fluid at the proper pressure passes into and through conduits 47 and 48 to four-way double solenoid spring centered directional valves 49 and 49a. To the valves 49 and 49a there is connected a pair of conduits 51 which .terminate at similar double reducing valves 52 and 53 having integral check valves provided therein. Also connected to the valves 49 and 49a there is a second pair of conduits 54 which terminate at similar reducing valves 55 and 56 having integral check valves also provided therein.

From FIG. 3 it is noted that valves 52 and 53 are connected to similar conduits 57, which, through conduits 58, communicate with the head ends of the double acting cylinders 25 and 32. The remaining pairs of valves 55 and 56 have connected thereto conduits 59 which,

' through conduits 61, communicate with the piston rod end of the double acting cylinders 25 and 32. V

Also connected to the conduits 57 and 59 there are pressure gages 62 for indicating the pressure of the fluid being delivered to double acting cylinders. In the same lines and adjacent to the pressure gages 62 there are relief valves 63 which function to relieve the lines of pressure in excess of that desired in the cylinders and to return fluid bled therefrom to the sump. If pressure is to be imposed at the head end of the cylinders 25 and 32 then the valves 55 and 56 are closed so that fluid from the piston rod end of the cylinders will be returned to the sump by the conduit 64 indicated in dotted lines. When pressure is to be applied to the piston rod ends of the cylinders then, of course, the valves 52 and 53 are closed so that the fluid is drained from the head end of the cylinders through conduit 64 to the sump.

As shown in FIG. 4, the electrical circuit includes lines L L and L connected to a main source of power, not shown, with the lines connected to three-pole open switch CB which in turn are connected through contacts M and two thermal overload relays 0L and 0L to a motor MR. The two main lines L and L, are also connected through switches CB to one side of a transformer TR. At the low voltage side of the transformer there are connected two conductors L and L with two fuses FU-l connected therebetween as well as a normally open starting push button switch PS, a normally closed push button stop switch SS, two normally open sets and one normally closed set of contacts M, a relay coil M, two thermal overload relays 0L and 0L a red signal light SR and a green signal light SG. t

In, the second portion of the electrical circuit, there are connected between lines L and L a pair of fuses FU-2, a normally open push button switch POS, a normally closed push button off switch PCS, normally open contacts CR a contact M, a relay coil CR a yellow signal light SY and the solenoid SV of the solenoid valve 46.

For the remaining portion of the electrical circuit where the flow of fluid to either the head end or piston rod end of the double acting cylinders 25 and 32 is actually controlled, there are two fuses FU-3 connected between lines L and L as well as a normally open push button up switch PUS, a normally closed push button down switch PDS, normally open contacts PRR, TDR and CR relay coils CR four of which are normally open and four of which are closed, solenoids SVZD and SV2U of valve 49 and solenoids SVSD and SV3U of valve 49A.

Finally, and as a safety measure, there are connected across the lines L and L a pair of fuses FU-4'connected in series with a pressure meter relay PRR connected to a pressure-meter of the customary well known type and therefore not specifically illustrated or described herein which is mounted in suitable slots provided in the posts of the mill housing, and two fuses FU-S connected in series with a photocell relay PER, connected to a photoelectric cell arrangement as shown at the entry side of the mill in FIG. 1.

' For purposes of illustration, let it be assumed that after considering the material to be rolled, the reduction to be taken, and the width of the strip being processed it is determined that the crown of the working rolls 14 and the supporting ultimate load carry-ing backing up rolls 16 is such that in order to produce a strip of uniform thickness the contour controlling bending moments are to be so applied as to how the bodies of the supporting rolls in a direction toward the processing rolls. For the mill shown in FIG. 1, this requires that the pressure he applied to the necks of the lower supporting roll in a downward direction and to the necks of the upper supporting roll in an upward direction. The operator will open one of the pairs of valves 52 or 53 depending upon the pressure to be applied to the supporting r-oll necks, each of the valves 52 and 53 being adapted'to deliver a given pressure within the ranges thereof. Since during a rolling operation high pressures will not be required to be applied to the necks of the supporting roll in a direction tending to separate those rolls, then assuming that valves 55 are the low pressure v-alves, these valves will be opened and valves 56 closed.

With the initial set up completed, the operator will actuate the screws of the mill to define the pass for the material to be rolled, the work rolls 14 actually not being pressed together with sufiicient force to load the mill housing and energize the pressure meter relay PRR.

The operator will then close the disconnect switches CB thereby causing the green signal SG to light indicating that the motor and pump are in readiness to run. In order to start the motor 37 and pump 36, the push button switch PS is depressed momentarily, thus energizing the relay coil M which locks in the open contact M and opens the normally closed con-tact M, thus causing the green signal SG to go out and the red signal SR to light which indicates that the motor 37 and pump 36 are running and circulating fluid from the sump 33 through the cooling tube 4 3 and back to the sump. If the pump is to be stopped for any reason, then it is only necessary to press the push button SS and all of the then closed contacts M will open, thus to stop the motor 37, shut-off the signal SR and close the remaining contact M to light the green signal-8G.

With the pump running, the valve 46 is opened by depressing momentarily the push button POS, thus energizing the relay coil CR which locks in the contacts CR thereby energizing the solenoid SV and opening valve 46 and lighting the yellow signal SY to indicate that fluid under pressure is then being delivered to the valves 49 and 4911 through the valve 46.

It will be noted that as soon as the valve 46 is opened, as controlled by the solenoid 8V the solenoids SV2U and SV3U of valves 49 and 49a respectively are also energized, thus causing fluid to flow through the valves 49 and 49a to and through the valves 55 thereby applying pressure to the piston rod side of the double acting cylinders 25 and 3 2, thus to force the supporting rolls 'in a direction away from each other. However, as soon "as strip is entered into the mill, the photocell relay PER drops out, thus opening the normally closedcontact PER and deenergizin-g the relay coil TDR and the pressuremeter relay PRR becomes energized and closes contacts PRR. The operator then momentarily depresses the push button PUS which will energize the relay coil CR thus locking in the normally open contacts CR and opening .the normally closed contacts CR thereby deenergizing solenoids SVZU and SV'3U and energizing solenoids SV ZD and SV3D to reverse the valves 49 and 49a respectively causing pressure to be app-lied to the head end of the double acting cylinders 25 and 32, thus to apply pressure to the necks of the upper supporting roll in a downward direction and to the necks of the lower supporting roll in an upward direction.

As a safety feature to prevent the rolls from being literally slammed together either when the strip coil end passes through the mill or the strip breaks on the entry side of the mill, the photo rel-ay PER plays a significant part. Whether the strip breaks or the tail ends of the strip is approaching the mill the effect is the same, for as soon as the light beam at the photocell becomes uninterrupted, the time delay relay TDR will allow sufficient time for the strip to approach very closely to the bite of the rolls before it is deenergized to open the contact TDR. As soon as the contact TDR opens, the relay coil CR is deenergized, thereby causing the then locked in contact CR to drop out and to close the previously open contacts CR thus deenergizing the solenoids SVQD and SV3D and energizing the solenoids SVZU and SVSU which cause a reverse of flow of fluid to the double acting cylinders 25 and 32 so that pressure is applied to the necks of the supporting rolls in a direction to separate the rolls.

When rolling conditions are such that if, during roll: ing, pressure is to be applied to the necks of the supporting rolls in a direction to increase its crown, then, of

course, irrespective as to whether the mill is under load or not, the pressure on the necks of the supporting rolls will always tend to separate the rolls so that whether the strip breaks or the tail end passes through the mill, there will be no tendency of the rolls to slam together. In such a case, the proper valves 55 and 56 will be opened, depending upon the pressure to be applied to the necks of the supporting rolls, and the valves 52 and 53 closed. Then, the motor 37 and pump 36 are started by depressing the push but-tons POS momentarily which causes the contact CR to be locked in and the valve 46 to open as described above and so that pressure will be immediately applied through the valves 49 and 49a in the direction determined by the energized solenoids SVZU and SV3U to deflect the ends of the supporting rolls in a direction away from each other thus, in effect, to emphasize the crown of the rolls:

In FIGS. Sand 6 there is also illustrated a four-high rolling mill of which the rolls and portions of the housings and screwdown mechanism as shown bear the same identifying numerals as those of FIG. 1 and in which the features of the invention herein disclosed are embodied in modified form, there being but two double acting piston cylinder assemblies for imposing upon the mill backing up rolls the desired contour controlling bending moments. For this purpose, a piston cylinder assembly 71 is provided on either side of the mill, being located beneath the necks of the lower backing up roll. On the mill side of the cylinder, there are provided projections 72 which engage with and are free to slide vertically in guides 73 machined in the mill housings. A piston rod 74 extends upwardly from each of the piston cylinder assemblies and is secured to a bearing housing 75 secured to the necks of each of the lower backing up rolls. Hingedly secured to the sides of each of the cylinders there are two rods 76 which extend upwardly and are provided with enlarged ends 77 which are received in suitable slotted openings 78 machined in projections 79 extending outwardly from hearing housings 81 secured to the necks of the upper backing up roll. A readily detachable clip 82 is secured to each of the projections 79 and closes the gap at the openings 78 for preventing the rods 76 from inadvertently swinging outward and becoming disengaged from the housing 81. While the preferred embodiment of the invention includes a pair of piston cylinder assemblies for each backing up roll with suitable hydraulic and electrical controls therefor, the hydraulic system can be readily modified to provide fluid under pressure to either side of the double acting piston cylinder assemblies 71 thereby to impose a bending moment in the proper direction and of the required magnitude. In operation, when pressure is applied to the cylinders, for example, at the piston rod end of the cylinder, the reaction will be topull the necks of the bottom backing up roll downward to how the body of the lower backing up roll upward and, through the two rods 76 to push the necks of the upper backing rolls upward, thereby to how the bodies of the upper backing up roll arrangement. The assemblies 71, of course, slide freely in the guides 73. For counterbalancing the weight of the piston cylinder assemblies 71 and the elements connected thereto, there is provided for each of the cylinders a piston cylinder assembly 83, mounted beneath the assemblies and secured to a rail 84 extending across and beneath the housing. The assemblies 83 are maintained under a constant pressure for this purpose.

Another modification of the invention is shown in FIGS. 7 and 8 in which one form of a cluster mill commonly referred to as an X-mill is illustrated. This mill comprises a housing 91 in which there are positioned a pair of working or processing rolls 92, a separate additional roll 93 in contact with each of the working rolls 82, but not in contact with each other, and a separate supporting or ultimate load carrying roll 94 in contact with and supporting each of the additional rolls 93. On

the necks of each of the ultimate load carrying rolls there is aflixed a bearing housing 95 to each of which there are pivotally connected at one of their ends by readily disengageable pins 96 two rods or bars 97, which bars are It will be appreciated that the hydraulic system, incor-.

porated in the four-high embodiment of invention shown in FIG. 1, could be readily modified to admit fluid under controlled pressure to either of the ends of all of the double acting piston cylinder assemblies 101 merely by connecting all of the piston cylinder assemblies to the conduit-s 58 and 61. Thus, a contour controlling bending moment may be readily applied to the ultimate load supporting rolls of the mill which will so control the contour of the mill that a product of uniform thickness across its width will be produced.

It will thus be recognized, therefore, that whether the features of the invention as disclosed herein are embodied in strip processing rolling mills having supporting or ultimate load carrying rolls either in direct contact with or remotely positioned with respect to the processing or working rolls of the mill, the effect of the application of a contour controlling bending moment to such supporting or ultimate load carrying rolls when of the proper magnitude and direction, as determined by the characteristics of the strip being rolled, i.e,, thickness, width, metallurgical analysis as well as the reduction to be taken, will be to produce a strip of'uniform thickness across its width.

In accordance with the patent statutes I have explained the principle and operation of by invention and have illustrated and described what I consider to represent the best embodiments thereof. However, I desire to have it understood thatwithin the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

, I claim:

1. In a rolling mill, a housing, a pair of small diameter working rolls, a pair of chocks for each of said rolls slidably mounted in suitable openings provided in said hous ing, at least one relatively large diameter supporting ultimate load carrying roll for each of said working rolls,

said load carrying roll having an enlarged diameter roll body and reduced diameter necks extending from the ends thereof, roll adjusting means secured to the necks of and for raising and lowering at least one of said supporting rolls and controllable pressure applying means operably engaged with the necks of and for imposing upon said supporting rolls a contour controlling bending moment outward of said roll adjusting means whereby on the application of pressure of said rolls by said controllable ressure applying means said rolls will be deflected in such a fashion as to compensate for the deflection thereof and of the working rolls incident to forces imposed thereon during a rolling operation thereby to provide a uniform pass across the width of said work rolls.

2. In a rolling mill according to claim 1 in which said pressure applying means comprises a pair of cylinders secured to said housing, piston rods extending from each of said cylinders and connected to the necks of at least one of said supporting ultimtae load carrying rolls and means for introducing fluid under pressure to apply a contour controlling bending moment of such magnitude and direction as to so deflect said supporting and said working rolls to compensate for the normal deflection thereof resulting from a rolling operation thereby to provide a uniform pass across the width of said working rolls.

3. In a rolling mill according to claim 1 in which said supporting rolls are crowned and said pressure applying means comprises a pair of double acting cylinders secured to said housing adjacent to and above the upper of said supporting rolls, a pair of double acting cylinders secured to said housing adjacent to and below the lower of said supporting rolls, piston rods extending from said cylinders and secured to the necks of said supporting ultimate load carrying rolls adjacent thereto, and fluid directional and pressure controllable means operably connected to each of said double acting cylinders whereby during a rolling operation fluid will be introduced into said double acting cylinders to apply a contour controlling bending moment of such magnitude and direction as to compensate both for the crown and the eifect thereon resulting from deflection of said rolls normally caused during a rolling operation thereby to provide a uniform pass between the working rolls and across the width thereof.

4. In a rolling mill according to claim 1 in which readily detachable means are interposed between and for connecting said pressure applying means to the necks of said ultimate load carrying supporting rolls.

5. In a rolling mill according to claim 1 in which said controllable pressure applying means comprises a separate piston rod connected to each of the necks of one of said ultimate load carrying supporting rolls, a separate double acting cylinder from which each of said piston rods extend and means connecting said cylinders to the necks of the other of said supporting rolls.

6. In a rolling mill according to claim 5 in which guide means are included and slidably engaged with said double acting cylinders.

7. In a rolling mill according to claim 5 in which said means connecting said cylinders to the necks of the other of said supporting rolls includes a pair of rods hingedly connected at one end of each of said cylinders, and readily detachable means connecting the opposite ends of said rods to the necks of said roll.

8. In a rolling mill according to claim 6 in which yieldable counterbalancing means are included and operably engaged with said separate double acting cylinders.

9. In a rolling mill, a housing, a pair of small diameter crowned upper and lower workingrolls, a pair of chocks for each of said rolls slidably mounted in suitable windows provided in said housing, a relatively large diameter crowned supporting roll for each of said working rolls, a pair of chocks for each of said supporting rolls also slidably mounted in the windows of said housing, a pair of screws secured to said housing and operably engaged with at least one of said supporting rolls, means for adjusting said screws to define a pass between said working rolls, a pair of double acting cylinders secured to said housing adjacent to and above the supporting roll of said upper working roll and a pair of double acting cylinders secured to said housing below the supporting roll of said lower working rolls, a pair of vertically aligned bearing housings secured to said supporting rolls outboard of the chocks thereof, a piston rod extending from each of said cylinders and detachably secured to the bearing housings of said supporting rolls most adjacent thereto and controllable pressure applying means adapted to actuate the piston rods of said cylinders in such a direction and under such pressure as to impose upon said supporting rolls a contour controlling bending moment sufficient to compensate for normal deflection incident to a rolling operation thereby to define a uniform pass across the width of said working rolls.

' It). In a rolling mill, a housing, a pair of small .diameter upper and lower working rolls, a relatively large diameter backing up roll for each of said working rolls, roll adjusting screws in engagement with and for applying pressure to and for adjusting said backing up rolls to define a pass between said working rolls, and controllable pressure applying means operably engaged with the necks of said backing up rolls comprising a pump, a pair of double acting cylinders, pistonrods extending from said cylinders and operably engaged with the necks of said backing up rolls at points displaced along the axes of said rolls with respect to the points at which pressure is applied by said adjusting screws, pressure limiting valve means interconnecting said pump with said cylinders and additional valve means interposed between said pressure limiting valve means and said cylinders operable to direct fluid under pressure in the proper direction to said cylinders thereby to apply a contour controlling bending moment to the necks of said backing up roll, thus to compensate for the deflection of said backing up and said working rolls and to define a uniform pass across the width of said Working rolls.

11. In a rolling mill according to claim in which fluid direction control means is included in combination with said controllable pressure applying means adapted to direct fluid into said double acting cylinders in such a manner as to cause pressure to be applied to and to urge said backing up rolls away from one another when the mill is in an unloaded condition.

12. In a rolling mill according to claim 10 including photocell control means operably arranged with respect to said controllable pressure applying means and adapted upon the approach of the strip trailing end portion into the region adjacent to the bite of the mill to assure the introduction of fluid under pressure into said double acting cylinders in such a manner as to urge said backing up rolls away from one another prior to passage of the strip trailing end portion through the mill.

13. In a rolling mill, a housing, a pair of small diameter rolls, at least one relatively large diameter supporting ultimate load carrying roll for each of said working rolls, roll adjusting means secured to the necks of and for raising and lowering at least one of said supporting rolls and controllable pressure applying means operably engaged with the necks of and for imposing upon at least one of said supporting rolls a contour controlling bending moment whereby on the application of pressure to the necks of said roll by said last mentioned means said roll will be deflected in such a fashion as to compensate for the deflection thereof and of the working roll supported thereby incident to forces imposed thereon during a rolling operation thereby to maintain the axis of said working roll straight.

14. In a rolling mill according to claim 13 in which readily releasable means are interposed between said pressure applying means and the necks of said supporting roll for disengaging said pressure applying means from the necks of said roll. v

15. A rolling mill according to claim 13 in which each of said work rolls is supported by a pair of ultimate loadload-carrying rolls and said working rolls and wherein controllable pressure-applying means is secured to the necks of the ultimate load-carrying rolls.

16. In the method of forming in a rolling mill strip material of a uniform thickness throughout the width thereof the steps comprising reducing the strip between a pair of relatively small diameter Working rolls each having a relatively large diameter supporting ultimate load carrying roll operatively engaged therewith across the working face thereof, applying a contour controlling bending moment to the ends of said supporting rolls outward of the working faces of said work rolls and in such a direction and of such a magnitude as to oppose and compensate for the deflection of said working rolls thereby to define a uniform pass across the width of said working rolls.

References Cited in the file of this patent UNITED STATES PATENTS 685,468 10/1901 Faweel --56 1,708,185 4/1929 Mattei 8056 2,039,959 5/1936 Iverson 8038 2,042,871 6/1936 Talbot 80--38 2,271,459 1/1942 McConnell 8038 2,339,359 1/1944 Shayne 8056 2,368,030 1/1-945 Larsson 80-38 2,430,410 11/1947 Pauls 80-56 2,611,150 9/1952 Goulding 80--56 2,738,663 3/1956 Moore 170 2,825,217 3/1958 Byrd 80-56 X 2,897,538 8/ 1959 Shapiro et al. 8056 2,903,926 9/1959 Reichl 8056 3,060,843 10/1962 Moore et al.

3,085,503 4/1963 Moore.

FOREIGN PATENTS 747,347 4/ 1956 Great Britain.

OTHER REFERENCES Westinghouse Engineer, pages 40 and 41, March, 1957 copy in 80-56E.

CHARLES W. LANHAM, Primary Examiner.

THOMAS E. BEALL, WILLIAM W. DYER, JR., W. A.

SCHEEL, Examiners.

R. MILLER, C. HITTSON, L. O. MAASSEL,

Assistant Examiners. 

1. IN A ROLLING MILL, A HOUSING, A PAIR OF SMALL DIAMETER WORKING ROLLS, A PAIR OF CHOCKS FOR EACH OF SAID ROLLS SLIDABLY MOUNTED IN SUITABLE OPENINGS PROVIDED IN SAID HOUSING, AT LEAST ONE RELATIVELY LARGE DIAMETER SUPPORTING ULTIMATE LOAD CARRYING ROLL FOR EACH OF SAID WORKING ROLLS, SAID LOAD CARRYING ROLL HAVING AN ENLARGED DIAMETER ROLL BODY AND REDUCED DIAMETER NECKS EXTENDING FROM THE ENDS THEREOF, ROLL ADJUSTING MEANS SECURED TO THE NECKS OF AND FOR RAISING AND LOWERING AT LEAST ONE OF SAID SUPPORTING ROLLS AND CONTROLLABLE PRESSURE APPLYLY MEANS OPERABLY ENGAGED WITH THE NECKS OF AND FOR IMPOSING UPON SAID SUPPORTING ROLLS A CONTOUR CONTROLLING BENDING MOMENT OUTWARD OF SAID ROLL ADJUSTING MEANS WHEREBY ON THE APPLICATION OF PRESSURE OF SAID ROLLS BY SAID CONTROLLABLE PRESSURE APPLYING MEANS SAID ROLLS WILL BE DEFLECTED IN SUCH A FASHION AS TO COMPENSATE FOR THE DEFLECTION THEREOF AND OF THE WORKING ROLLS INCIDENT TO FORCES IMPOSED THEREON DURING A ROLLING OPERATION THEREBY TO PROVIDE A UNIFORM PASS ACROSS THE WIDTH OF SAID WORK ROLLS. 